This invention relates to a waste separator which is associated with a carding machine. Underneath the main carding cylinder cover elements are arranged which are thus situated between the doffer and the licker-in and which define openings (also referred to as waste-removal or waste-discharge openings) for the separation of trash, dust and the like from th fiber material worked by the carding cylinder. The openings are bounded by mote knives secured to the cover elements. In known arrangements of this type the waste which exits the waste-removal openings falls into a lower card space which is exposed to suction. Due to the air which is generated by the rotation of the carding cylinder and which rushes out through the waste-removal openings and because of the non-uniform suction effect over the entire lower carding space, disadvantageous turbulences are generated therein. Since above the carding cylinder, that is, between the licker-in and the doffer as viewed in the direction of rotation of the carding cylinder, larger waste particles have already been removed particularly by the travelling flats, by means of the mote knives situated underneath the carding cylinder between the doffer and the licker-in finer impurities including dust are being removed. Such finer impurities and dust are disadvantageously swirling under the effect of the non-uniform air flows in the lower carding space. As a result, they tend to settle in the corners of the lower space of the carding machine in case they are not entrained by the suction stream.